Social ascent changes cognition, behaviour and physiology in a highly social cichlid fish.

When an individual ascends in dominance status within their social community, they often undergo a suite of behavioural, physiological and neuromolecular changes. While these changes have been extensively characterized across a number of species, we know much less about the degree to which these changes in turn influence cognitive processes like associative learning, memory and spatial navigation. Here, we assessed male Astatotilapia burtoni, an African cichlid fish known for its dynamic social dominance hierarchies, in a set of cognitive tasks both before and after a community perturbation in which some individuals ascended in dominance status. We assayed steroid hormone (cortisol, testosterone) levels before and after the community experienced a social perturbation. We found that ascending males changed their physiology and novel object recognition preference during the perturbation, and they subsequently differed in social competence from non-ascenders. Additionally, using a principal component analysis we were able to identify specific cognitive and physiological attributes that appear to predispose certain individuals to ascend in social status once a perturbation occurs. These previously undiscovered relationships between social ascent and cognition further emphasize the broad influence of social dominance on animal decision-making. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.

Intraductal papillary neoplasm of the bile duct.

Intraductal papillary neoplasm of the bile duct is characterized by intraductal papillary growth with fibrovascular cores that can grow anywhere along the biliary tree. Most cases have high-grade intraepithelial neoplasia or an associated invasive carcinoma. These tumors can spread superficially along the biliary tree and be multifocal, and preoperative biopsy cannot always reflect the maximum degree of atypia. Frozen section to assess the distal common bile duct margin is crucial to avoid the risk of recurrence. Theoretically, resection of the entire biliary tree by liver transplantation and pancreaticoduodenectomy is regarded as the only curative treatment.

Plasmablastic plasmacytoma of the breast.

Breast plasmacytomas are extremely rare entities that can be seen as primary malignant neoplasms in the absence of bone involvement or as secondary neoplasms from disseminated multiple myeloma. Clinicians should be aware of this entity, as it may mimic benign and malignant lesions in the breast. Microscopically, immature plasmacytomas may mimic other neoplasms, so caution should be made on histological examination to ensure the correct diagnosis and corresponding therapy. Here we present a case of a plasmablastic plasmacytoma of the breast in a 55-year-old woman that was originally thought to be an angiosarcoma.

Giant cystic umbilical cord associated with patent urachus and intrauterine fetal demise.

True cystic structures within the umbilical cord are rare, and when they persist into the second and third trimester, they are often associated with an abnormal karyotype or other developmental abnormalities. Clinically significant pseudocysts resulting from massive edema of the umbilical cord have been associated with a congenitally patent urachus. We present a case of intrauterine fetal demise at 28 weeks' gestation in which cystic dilatation of the umbilical cord was diagnosed prenatally by ultrasound imaging. At autopsy, a congenitally patent urachus was contiguous with the massively edematous umbilical cord.

Abdominal apoplexy resulting in small bowel obstruction.

Abdominal apoplexy is a rare hemorrhagic condition involving the small arteries or veins within the abdominal cavity. A high degree of clinical suspicion, followed by appropriate diagnostic workup and therapeutic intervention, is critical, as nonoperative mortality approaches 100%. Contrary to most previously reported cases, which were associated with hemoperitoneum, we present a patient in which gastroduodenal artery dissection resulted in an organized retroperitoneal hematoma with local compression of the duodenum and subsequent bowel obstruction, resulting in vomiting, aspiration, and death.

Predictors of Staphylococcus aureus Colonization and Results after Decolonization.

Protocols for the screening and decolonization of Staphylococcus aureus prior to total joint arthroplasty (TJA) have become widely adopted. The goals of this study were to determine: (1) whether implementation of a screening protocol followed by decolonization with mupirocin/vancomycin and chlorhexidine reduces the risk of revision compared with no screening protocol (i.e., chlorhexidine alone) and (2) whether clinical criteria could reliably predict colonization with MSSA and/or MRSA. Electronic medical records of primary patients undergoing TJA that were screened (n = 3,927) and were not screened (n = 1,751) for Staphylococcus aureus at least 4 days prior to surgery, respectively, were retrospectively reviewed. All patients received chlorhexidine body wipes preoperatively. Patients carrying MSSA and MRSA were treated preoperatively with mupirocin and vancomycin, respectively, along with the standard preoperative antibiotics and chlorhexidine body wipes. Screened patients were 50% less likely to require revision due to prosthetic joint infection compared to those not screened (p = 0.04). Multivariate regression models were poorly accurate in predicting colonization with MSSA (AUC = 0.58) and MRSA (AUC = 0.62). These results support the routine screening and decolonization of S. aureus prior to TJA.